/*
 * Licensed to Crate under one or more contributor license agreements.
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.  Crate licenses this file
 * to you under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License.  You may
 * obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial
 * agreement.
 */

package io.crate.expression.reference.doc.lucene;

import io.crate.metadata.doc.DocSysColumns;
import io.crate.execution.engine.collect.collectors.CollectorFieldsVisitor;
import org.apache.lucene.util.BytesRef;

public class UidCollectorExpression extends LuceneCollectorExpression<BytesRef> {

    public static final String COLUMN_NAME = DocSysColumns.UID.name();

    private CollectorFieldsVisitor visitor;

    public UidCollectorExpression() {
        super(COLUMN_NAME);
    }

    @Override
    public void startCollect(CollectorContext context) {
        context.visitor().required(true);
        this.visitor = context.visitor();
        this.visitor.addField("_uid");
    }

    @Override
    public BytesRef value() {
        return visitor.uid().toBytesRef();
    }
}
